close all
v=[0.8 0.6];
w=[-1 0.5]
o=[0 0];

ceuArrow(o,v,'b',2)
ceuArrow(o,w,'b',2)
ceuArrow(w,v,'r',2)
text(v(1)+0.1,v(2)+0.1,'v','FontSize',14)
text(w(1)-0.1,w(2)+0.1,'w','FontSize',14)
text(-0.25,0.9,'||v-w||','FontSize',14)
axis([-1.5 1.5 -1.5 1.5])
axis square
grid on
xlabel('x_1')
ylabel('x_2')

alpha_u=atan2(v(2),v(1));
alpha_w=atan2(w(2),w(1));
alpha=alpha_u:0.001:alpha_w;
plot(0.25*cos(alpha),0.25*sin(alpha),'k:','Linewidth',2)
text(0,0.35,'\theta','FontSize',14)
